Just recently with the warmer weather, my tank has been getting much warmer than usual...almost 80-81 degrees. Happens slowly over the course of the day with the lights turned on...not at night. I'm thinking that perhaps the fan is not cooling the way it should be? This is a 4 bulb Coral Life T5 set-up. Does anyone know how to replace that little fan on top or where I should look for a new one? I'm in Fond du Lac. and am not very handy LOL---thanks!

Starboard's idea is a good one. Modding lighting fans takes a bit of DIY skill.

The fan on the fixture isn't going to keep the light from passing heat into the tank; it is meant mostly to cool the fixture itself so it runs more efficiently. Running a fan across the surface of the tank water will help to keep the tank temp down (by increasing evaporation, so watch the salinity closely).